The Role of Antarctica and the Southern Ocean in Past, Present and Future Climate: A Strategy for th

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Climate of Antarctica and the Southern Ocean
(CASO)
S. Rintoul, E. Fahrbach and I. Renfrew on behalf
of the CLIVAR/CliC/SCAR Southern Ocean Panel
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SO role in climate
Rintoul, 2001
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Carbon uptake
Sabine et al., 2004
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Rapid change in polar regions
http//www.nsidc.org/iceshelves/larsenb2002
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Southern Annular Mode
30 year trend
Congruent with SAM
Thompson and Solomon, 2002
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Teleconnections
Yuan et al., 2004
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Sea ice and margin processes
Massom et al., Annals of Glaciol, 33, 391-398,
2001
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Climate research themes for the IPY

• Antarctica and the Southern Ocean in the global
  water cycle
• Southern hemisphere teleconnections
• Climate processes at the Antarctic continental
  margin
• Climate ecosystem biogeochemistry
  interactions in the Southern Ocean
• Records of past Antarctic climate variability and
  change

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Tackling key unknowns

• CASO will
• Obtain the first circumpolar snapshot of the
  Southern Ocean, including physical, ecological
  and biogeochemical properties.
• Measure the circumpolar extent and thickness of
  Antarctic sea ice through an annual cycle for the
  first time.
• Observe the sub-ice ocean circulation, water mass
  properties and biological distributions

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IPY Observing System

• Synoptic multi-disciplinary transects
• Sea ice volume
• Enhanced sea ice drifter array
• Ocean circulation under sea ice
• Enhanced Southern Ocean Argo
• Enhanced meteorological measurements
• Ice cores from high accumulation rate coastal
  sites
• Process studies

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Ocean Circulation Cluster

• CASO vision too large to provide a practical
  vehicle for implementation
• IPY decided to cluster projects along discipline
  or regional lines
• CASO (and Southern Ocean panel) given
  responsibility for Antarctic Ocean Circulation

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Synoptic multi-disciplinary transects
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Argo float array as of 13 April 2005 (red dots).
Under-ice observing systems (blue). AUV
sampling (green transects).
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DIMES
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Antarctic Dipole
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Potential gaps

• Modelling
• Argo, open ocean and under ice
• Zonal lines in subtropics
• Other sections?
• ACC transport monitoring

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Challenges

• Coordination between clusters and projects
• Synthesis how do we ensure the original CASO
  vision is realised?
• Time is short